Aluminium oxide is impermeable and, unlike the oxide layers on many other metals, it adheres strongly to the parent metal. If damaged mechanically, aluminiumâs oxide layer repairs itself immediately.
Saliva helps remove oral waste and cavity-causing bacteria, protects teeth from decay by neutralizing harmful acids, and helps re-mineralize tooth enamel. Saliva also keeps oral tissues healthy by preventing infection by controlling bacteria and fungi in the mouth.
Saliva. Saliva or spit is a watery substance produced in the mouths of many animals, including humans, and is a vital element of their digestive process. Saliva basically commences the digestive process by moistening the ingested food. This watery, often frothy, substance is produced in the salivary glands.aliva. Saliva or spit is a watery substance produced in the mouths of many animals, including humans, and is a vital element of their digestive process. Saliva basically commences the digestive process by moistening the ingested food. This watery, often frothy, substance is produced in the salivary glands.